1. Field of the Invention
The present invention relates to multiple disc type engaging devices, such as multiple disc clutches, multiple disc brakes and the like, installed in an automatic transmission.
2. Description of the Prior Art
In order to clarify the task of the present invention, one conventional multiple disc type engaging device will be described, which is shown in "SERVICE MANUAL" volume 599 issued May, 1988 from NISSAN MOTOR CO., LTD.
The device is a forward clutch of multiple disc type, which is partially shown in FIG. 3 of the accompanying drawings.
The forward clutch comprises a hub 01 which is constructed to have a cylindrical barrel portion 02. The barrel portion 02 has at its one end an annular flange 03 bent radially inwardly. An outer surface of the barrel portion 02 is formed with a plurality of axially extending splines 05 with which annular drive discs 04 are meshed. For this meshed engagement, each annular drive disc has a plurality of teeth. The annular flange 03 has a leading end portion 06 bent axially outwardly with respect to the barrel portion 02 and secured to an outer race 08 of a forward one-way clutch 07.
In order to increase the torque transmitting capacity of the forward clutch, the number of discs 04 is increased. Thus, in this case, the length of the barrel portion 02 should be increased. However, elongation of such barrel portion 02 is substantially impossible because of a limited space for the hub 01 in the transmission housing. Furthermore, if the length of the barrel portion 02 is increased, the axially extending part 06 of the annular flange 03 becomes short in length. This means a lowering of the connecting force with which the hub 01 is coupled with the outer race 08.